Safety-plug for steam-boilers.



Patented Nov. [4, I899.

C. E. RHOADES. SAFETY PLUG FOB STEAM BOILERS.

(Application filed July 26, 1899.)

(No Model.)

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CHARLES E. RHOADES, OF FOSTORIA, OHIO.

SAFETY-PLUG FOR STEAM-BOILERS.

sPEcrFrcA'rIoNrormm part of Letters Patent No. 636,845, dated November 14,1899. Application filed July 26,1899. Serial No. 725,187. (No model.)

To aZZ whom it may concern.-

Be it known that 1, CHARLES E. RHOADES, a citizen of the United States, residing at Fostoria, in the county of Seneca and State of Ohio, have invented a new and useful Safety- Plugfor Steam-Boilers, of which the following is a specification.

This invention relates to safety-plugs for steam-boilers, and particularly to that char-- acter of such devices employing a fusible member; and the object of the present invention is to provide an attachment of the nature set forth for steam-boilers which is so constructed and located that when the water reaches too low a level in the boiler or the crown-sheet or upper plate of the fire-box is not covered with water, and henceis intensely heated, the fusible member of the plug will be reduced and blown out and establish communication between the boiler and the firebox for the introduction of steam into the latter to relieve the pressure within the boiler and also extinguish the. fire.

The invention consists of the construction and arrangement of the parts, which will be more fully hereinafter described and claimed.

In the accompanying drawings, Figure l is a longitudinal vertical section of a boiler and fire-box, showing the improved safety-plug applied to the crown-sheet. Fig. 2 is a bottom plan view of the plug. Fig. 3 is a transverse vertical section of the plug. Fig. 4 is a similar section taken at a difierent angle. Fig. 5 is an elevation of the improved device.

Similar numerals of reference are employed to indicate corresponding parts in the several views. p

The numeral 1 designates a boiler having a fire-box 2 positioned in relation thereto in the ordinary manner and provided with a crown-sheet 3, which, as understood, is directly exposed to the boiler. The improved safety-plug is fitted in the crown-sheet 3 and composed of a shell or casing 4, having a head 5 formed with exterior wrench or nut engaging faces 6. The exterior of the shell 4 is screw-threaded, as at 7, and coincides with corresponding threads formed in the crownsheet 3 at the point where the plug is applied. The head 5 has a bore 8 therethrough, which is tapered inwardly toward the chamber of the end of the shell opposite that on which the head 5 is formed. A flat edge 10 of the bridge is thus located adjacent the entrance of the bore Sin the chamber of the shell, and in the said bore is removably fitted a fusible stem 11, preferably composed of Babbitt metal and tapered, and in the original or initial arrangement the said stem is driven into the head 5 and the inner end swaged or slightly upset against the edge 10 of the bridge 9. By this mode offastening the stem in the plug said stem is prevented from becoming disengaged from the head 5 under ordinary pressure conditions, and fusion must first ensue before the stem will be free to be driven from its secured position. It is intended that fusion of the stem 11 ensue only when the crown-sheet 3 will have become intensely and dangerously heated owing to the clearance of water therefrom and at a time when immediate relief is necessary not only to reduce the pressure in the boiler, but simultaneously quench or extinguish the fire in the fire-box 2, and when this fusion takes place the steam passes from the boiler through the shell 4, and through the intersection of the bridge 9 is divided and covers a greater surface of the fire, thus more rapidly extinguishing the latter.

The shell 4, with its head 5, together with the bridge 9, will be preferably formed of brass, and, as before indicated, remain in the crown-sheet, and after the stem 11 has been fused and blown out another can be quickly inserted and swaged against the bridge 9, as in the first instance.

The improved device can be readily applied in position and is not subject to interference in its operation by the collection thereon of scale or sediment, and a clear opening for the passage of steam from the boiler to the fire-box is instituted.

The stem 11 is tapered similarly to the bore 8 in the head 5, so that when driven into the head it will be more firmly secured, in

addition to the swaging which takes place through the medium of the flat edge of the bridge 9.

Changes in the proportions, size, and minor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

Having thus described the invention, what is claimed as new is 1. In a device of the character set forth, comprising a shell having a head with a bore therethrough at one end and inclosing a chamber, a transverse bridge in the chamber adjacent the terminal of the bore, a fusible plug adapted to be inserted in the bore and have its one end bear on and be upset against the bridge.

2. A device of the character set forth, comprising a shellwith a head,the said head inclos= ing a chamber and a bore tapered and opening into said chamber, a transverse, wedgeshaped bridge mounted. in the shell adjacent the point of communication of the bore therewith, and a fusible tapered stem adapted to be driven into the said bore and swaged against the bridge.

3. A device of the character set forth, comprising a shell with a bridge therein, and a fusible stem adapted to be driven into a part of the shell and have one end swaged by the bridge.

In testimony that I claim the foregoing as my own I have hereto affixed my signature in the presence of two Witnesses;

CHARLES E. RHOADES.

Witnesses:

G. W. REYNOLDS, W. F. BOLEY. 

